Compact dual-band antenna array for environmental monitoring systems

A portable, high-resolution, ground-based synthetic aperture radar is essential for effective environmental monitoring. This paper presents a compact microstrip antenna array with dual bands and dual polarizations. This antenna will be integrated into a radar system to aid disaster mitigation efforts. The proposed antenna array consists of 1 × 4 driven elements for each of the three input/output ports; each driven element is coupled to four parasitic patches for bandwidth enhancement, with two shared parasitic patches between each pair of adjacent driven patches. Two of these ports support vertical polarization and operate in the X-band, achieving a bandwidth of 0.52 GHz. In contrast, the third port supports horizontal polarization and operates in the Ku-band, achieving a bandwidth of 0.67 GHz. The proposed design comprises four stacked layers: the lowest layer is dedicated to the feeding network, followed by a ground layer with rectangular apertures for excitation. On top of the ground layer, a third layer contains the driven patches, and the fourth layer holds the parasitic elements. Using two different substrates, the prospective antenna has a 67.2 mm × 71.1 mm size. The dielectric constant for ground plane layer is 3.48 with height of 0.762 mm while the driven and parasitic patches are on another substrate with dielectric constant of 2.2 for better radiation and height of 1.57 mm. In the X-band, the half-power beamwidth (HPBW) is 80° in the E-plane and 28.5° in the H-plane. In the Ku-band, the HPBW is 35.2° in the elevation plane and 15.6° in the horizontal plane. The antenna acquires gain of 11.17 dBi in the X-band and 14.22 dBi in the Ku-band which is suitable for environmental monitoring system applications.